FAQs

What is photovoltaic solar energy?

The sun is a huge source of energy in the form of heat and light. Unlike thermal systems, photovoltaic solar panels or PV modules use only sunlight, not heat. They absorb the sunlight and transform it into electricity – with no emissions of harmful substances.

Is the energy for PV modules inexhaustible?

When you opt for solar panels, you are opting for a clean, inexhaustible, inexpensive and safe energy source. Sunlight is free and abundant, even on a cloudy day, because the solar cells work with diffuse light.

What is the difference between a solar collector and a solar panel?

In a solar collector, water is heated by sunlight. In a solar panel, the sunlight is converted directly into electrical power.

Can I use my PV system to heat water or to heat part of my house?

It is best not to do this. Photovoltaic cells convert solar energy into direct current with an efficiency level of 14-16%. So trying to power a high-consumption electrical system with PV would be inefficient. A solar water heater is much more efficient for applications of this kind.

How do solar cells work?

Solar cells or solar photovoltaic cells are generally made of silicon. They consist of a thin plate with a negative charge on the top layer and a positive charge on the bottom layer. Under the effect of light, an electric current is created between the two layers. At that point, an electric voltage is generated between the positively charged lower layer and the negatively charged top layer of the cell. Thin metal strips at the front of the cell absorb the electric current that is generated. These elements are connected by the electrical application to a small metal plate on the back of the cell. Depending on the type of silicon, the cell will convert a larger or a smaller proportion of the sunlight into electricity.
A solar cell therefore converts light directly into electricity. This direct current can be used to charge batteries or to operate small appliances directly. And after conversion into alternating current, solar power can also be delivered to the electricity grid.

How do solar panels work?

Photovoltaic systems consist of solar cells which are interconnected in PV panels. These panels convert sunlight into direct current (DC), which is in turn converted into alternating current (AC) by an inverter to be compatible with the electricity grid.

What is the difference between a standalone system and a grid-connected system?

When light hits a photovoltaic module, direct current is produced. This current can be used to operate small appliances directly or charge a battery. This is what happens in a standalone system. In grid-connected photovoltaic systems, however, an inverter converts the direct current into alternating current with the same rating as the current of the electricity grid. As a result, all electrical appliances can operate at low voltage. When more current is produced than is being used, the excess current goes to the grid. In that case, the electricity meter runs backward. When there is not enough light (and therefore more current is consumed than is produced), electricity is taken from the electricity grid to make up the shortfall. The electricity meter then runs forward again.

What do kWh and kW peak mean?

1 kWh (energy) = 1 kilowatt (power) for 1 hour (time)
A 1000 W electric heater therefore consumes 1 kWh in 1 hour (full power).
The kW peak, the theoretical maximum power of a photovoltaic installation is determined by the power delivered by the same system under standard conditions of sunlight (1000 W/m²), temperature (25°C) and standardisation of the light spectrum (AM 1,5).

What does PV mean?

This is the abbreviation for photovoltaic.

What is the best place for a photovoltaic installation?

The output of a solar panel depends not only on its size, but also on the angle of inclination and the position of the roof. If the angle of inclination is between twenty and sixty degrees, OK. Ideally, solar panels should be oriented towards the south, but a system pointing southeast or southwest can also yield 95% of the maximum electricity production.

We get very little sunshine. Would it make sense to generate solar energy here?

Diffuse sunlight is light that is scattered by clouds and particles in the atmosphere. Here in Belgium, around 60% of sunlight is diffuse. Fortunately, solar panels can also convert diffuse light into electricity, so a solar cell works even when it’s cloudy or when it’s raining. Therefore, on average a solar panel in southern Europe generates only 1.5 times more energy than in Belgium.

How environment-friendly are solar panels? What is the energy payback period?

The energy payback period is the time that a solar installation takes to generate the same amount of energy as the energy that has been consumed to produce it. Studies show that this period, depending on the position of the solar panels, is between one and three years. In their entire service life, solar panels generate 9 to 17 times more energy than is required for their manufacture. Power plants that run on fossil fuels, however, can never recover the energy used in their construction, since new fuel is constantly being consumed. In addition, many of the silicon wafers which are the basic element of solar cells are produced in different parts of the world that use hydroelectric energy (e.g. Canada, Scandinavia and China).

Should solar panels be cleaned?

No. Thanks to the smooth surface of the tempered glass and the oblique position of solar panels, they are self-cleaning. However, if you nonetheless want to clean them, it is recommended that you use a mild, natural soap.

Do solar panels increase the risk of lightning?

No, solar panels do not increase this risk. Additional lightning conductors are required only for large installations, but only to avoid a voltage difference between the different panels if lightning strikes in the vicinity.

What is the difference between monocrystalline, polycrystalline and thin film cells?

In the production of monocrystalline silicon cells, rods are drawn from a silicon melt consisting of one large crystal (monocrystalline). Thin disks are cut from this cylinder. This method of production results in higher cell efficiencies, but it gives no indication of the efficiency of a panel. Originally, monocrystalline silicon came exclusively from chip production.
It is cheaper to produce polycrystalline cells. The liquid silicon is cast into blocks and cut into disks. When the liquid silicon solidifies, crystal structures of different sizes are formed. The efficiency of the solar cells is reduced because of the presence of defects on the interfaces of these crystal structures. However, unlike monocrystalline cylinders, rectangular solar cells can be made from polycrystalline blocks. This improves the efficiency of the panel surface and therefore often offsets the difference in efficiency compared with monocrystalline cells.
Thin film cells are produced when a photovoltaic active layer is deposited on glass or another substrate material. The layer thicknesses are in fact less than 1 µm (by comparison, the thickness of a human hair is 50-100 µm). The cost of producing thin film cells is already cheaper if we take into account only the lower material costs. However, the output of thin film cells is also far lower than that of “ordinary” cells. Thin film cells are now mainly used for small applications such as watches and pocket calculators or as a facade element. Nonetheless, there is no doubt that thin film cells will be increasingly important in the future.

Must the installation be protected from extreme weather?

Soltech solar panels are resistant to extreme weather conditions. Storm, snow, severe frost and hail are no problem.

Should I take out additional insurance for a photovoltaic installation?

You should consult your insurer on this. In 2009, solar panels were included in fire insurance policies. However, this does not mean that your entire installation is covered, including the inverter and the cabling. You should also confirm the nature of the insurance policy: fire damage, theft, force of nature, etc. For example, lightning strike is not always included.

Why opt for solar energy?

– It’s a green energy source
– Sunlight is free
– It’s inexhaustible
– Lower electricity bills
– No emissions of CO2, Sox, Nox, methane, etc.
– Reliable technology
– Adds value to your home or your business
– Shows you care!

What is the effect of shade?

Because solar panels are composed of solar cells connected in series, even partial shade can affect the functioning of the entire panel.

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